Post-Transplant Radiation Had No Impact on Survival in Patients with Refractory or Relapsed Diffuse Large B-Cell Lymphoma

Abstract

IntroductionHigh-dose chemotherapy followed by autologous hematopoietic cell transplantation (AHCT) offers cure for appropriate patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) sensitive to chemotherapy. Post-AHCT consolidative radiation therapy (RT) has been associated with improved outcomes in R/R DLBCL patients with bulky [based on computed tomography (CT)] disease after AHCT. We and others have demonstrated that patients with a Deauville score 4-5 (high-risk) on pre-AHCT FDG positron emission tomography (PET) have significantly worse outcomes as compared to those with Deauville 1-3 (low risk). We here examined the impact of consolidative post-AHCT RT in R/R-DLBCL patients with high-risk functional imaging based on Deauville score) on pre-transplant FDG PET scan on AHCT outcomes. Therefore, we retrospectively studied the effect of post-ASCT RT within 6 months after ASCT on survival in patients with R/R-DLBCL with high-risk pre-ASCT PET scans.MethodsWe retrospectively studied 193 consecutive adult patients with R/R-DLBCL identified from the Cleveland Clinic and University of Minnesota who had available pre-transplant FDG PET scans and adequate clinical follow-up. PET scans were re-reviewed and scored Deauville 4-5 were considered high risk. Patients that died within 6 months of ASCT (n=20) were excluded from the final survival analyses. Univariate analysis was performed using the Kaplan-Meier method, and the log-rank test was used to compare the subgroups.ResultsThe mean (SD) age of diagnosis was 54 (11) years and 61% patients were male. The mean follow-up for alive patients was 43 (32.6) months. We identified 69 patients with pre-transplant Deauville scores 4 (n=41) or 5 (n=28). Seventeen (25%) received RT at median 58 days post AHCT (IQR 39-79 days). Receiving post-ASCT RT did not impact overall survival in univariable (Figure 1) or multivariable analyses adjusted for age and gender.ConclusionWithin the limits of the study design, we did not observe a benefit to RT on overall survival in patients with RR-DLBCL with high-risk pre-AHCT PET scans. Alternative treatment approaches for high risk patients based on pre-transplant PET should be investigated in prospective clinical trials. High-dose chemotherapy followed by autologous hematopoietic cell transplantation (AHCT) offers cure for appropriate patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) sensitive to chemotherapy. Post-AHCT consolidative radiation therapy (RT) has been associated with improved outcomes in R/R DLBCL patients with bulky [based on computed tomography (CT)] disease after AHCT. We and others have demonstrated that patients with a Deauville score 4-5 (high-risk) on pre-AHCT FDG positron emission tomography (PET) have significantly worse outcomes as compared to those with Deauville 1-3 (low risk). We here examined the impact of consolidative post-AHCT RT in R/R-DLBCL patients with high-risk functional imaging based on Deauville score) on pre-transplant FDG PET scan on AHCT outcomes. Therefore, we retrospectively studied the effect of post-ASCT RT within 6 months after ASCT on survival in patients with R/R-DLBCL with high-risk pre-ASCT PET scans. We retrospectively studied 193 consecutive adult patients with R/R-DLBCL identified from the Cleveland Clinic and University of Minnesota who had available pre-transplant FDG PET scans and adequate clinical follow-up. PET scans were re-reviewed and scored Deauville 4-5 were considered high risk. Patients that died within 6 months of ASCT (n=20) were excluded from the final survival analyses. Univariate analysis was performed using the Kaplan-Meier method, and the log-rank test was used to compare the subgroups. The mean (SD) age of diagnosis was 54 (11) years and 61% patients were male. The mean follow-up for alive patients was 43 (32.6) months. We identified 69 patients with pre-transplant Deauville scores 4 (n=41) or 5 (n=28). Seventeen (25%) received RT at median 58 days post AHCT (IQR 39-79 days). Receiving post-ASCT RT did not impact overall survival in univariable (Figure 1) or multivariable analyses adjusted for age and gender. Within the limits of the study design, we did not observe a benefit to RT on overall survival in patients with RR-DLBCL with high-risk pre-AHCT PET scans. Alternative treatment approaches for high risk patients based on pre-transplant PET should be investigated in prospective clinical trials.